#include <REGX52.H>

unsigned char num = 0;

void Delay(unsigned int ms)	//@11.0592MHz
{
	unsigned char data i, j;

	while(ms--)
		{
			i = 2;
			j = 199;
			do
			{
				while (--j);
			} while (--i);

		}
}

void main()
{
	P2_0 = 0;
	while(1)
	{
		if(P3_1 == 0)
		{
			Delay(20);
			while(P3_1 == 0);
			Delay(20);
			
			if(num == 0)
				num = 7;
			else 
				num--;
			
			P2 = ~(0x01 << num);
		}
		
		if(P3_0 == 0)
		{
			Delay(20);
			while(P3_0 == 0);
			Delay(20);
			
			num++;
			if(num >= 8)
				num = 0;
			P2 = ~(0x01 << num);
		}
	}
}